The present invention relates to a process for preparing EDDN and/or EDMN by reaction of FACH with EDA, the conversion being performed in a reactor with short residence time. The present invention also relates to the preparation of TETA and/or DETA by conversion of the EDDN or EDMN thus prepared with hydrogen in the presence of a catalyst. The present invention further provides for the preparation of epoxy resins, amides or polyamides from the DETA or TETA obtained in accordance with the invention.
WO 2008/104579 and the prior art cited in WO 2008/104579 specify various preparation methods for EDDN and EDMN.
In WO 2008/104579, EDDN is prepared by reacting EDA with formaldehyde (FA) and hydrogen cyanide (HCN) with a molar ratio of EDA to FA to HCN of 1:1.5:1.5 to 1:2:2 [mol:mol:mol]. The preparation can be effected by a) reacting EDA with FACH with a molar ratio of EDA to FACH of 1:1.5 to 1:2, or b) preparing EDDN by reaction of an ethylenediamine-formaldehyde adduct (EDFA) with hydrogen cyanide with a molar ratio of EDFA to HCN of 1:1.5 to 1:2, or c) reacting EDA with a mixture of formaldehyde and hydrogen cyanide with a molar ratio of EDA to FA to HCN of 1:1.5:1.5 to 1:2:2, or d) reacting EDA simultaneously with formaldehyde and HCN with a molar ratio of EDA to FA to HCN of 1:1.5:1.5 to 1:2:2.
It is disclosed that these reactions are preferably performed at a temperature of 10 to 90° C. and at standard pressure to slightly elevated super-atmospheric pressure. Preferred reactors are described as being a tubular reactor or a stirred tank cascade. The reaction output formed is preferably worked up by distillation, first removing low boilers such as hydrogen cyanide in a first stage and removing water in a second distillation step. The remaining aminonitrile mixture may have a residual water content of preferably at least 10% by weight. WO 2008/104579 discloses, in the examples, residence times for the reaction of EDA with FACH in the range from 30 minutes to 2 hours.